A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1913600 can be evenly divided by 1 2 4 5 8 10 13 16 20 23 25 26 32 40 46 50 52 64 65 80 92 100 104 115 128 130 160 184 200 208 230 256 260 299 320 325 368 400 416 460 520 575 598 640 650 736 800 832 920 1,040 1,150 1,196 1,280 1,300 1,472 1,495 1,600 1,664 1,840 2,080 2,300 2,392 2,600 2,944 2,990 3,200 3,328 3,680 4,160 4,600 4,784 5,200 5,888 5,980 6,400 7,360 7,475 8,320 9,200 9,568 10,400 11,960 14,720 14,950 16,640 18,400 19,136 20,800 23,920 29,440 29,900 36,800 38,272 41,600 47,840 59,800 73,600 76,544 83,200 95,680 119,600 147,200 191,360 239,200 382,720 478,400 956,800 and 1,913,600, with no remainder.
Since 1,913,600 cannot be divided by just 1 and 1,913,600, it is not a prime number.